1. Field of the Invention
The present invention relates to a four-wheeled utility vehicle suitable for carrying goods in outdoor spaces or in wide indoor spaces and provided with a cabin frame (also called as a cab frame) surrounding a driver""s seat.
2. Description of the Related Art
Referring to FIGS. 6A and 6B showing a four-wheeled utility vehicle disclosed in Japanese Utility Model Publication No. Shou 63-202579, The four-wheeled utility vehicle has a body frame 10, four wheels, i.e., two front wheels 2 and two rear wheels 3, suspended from the body frame 10, a driving unit, such as an engine, mounted on the body frame 10, a driver""s seat 4 and a load-carrying platform 30xe2x80x2. The four-wheeled utility vehicle is often provided with wide tires suitable for traveling on rough roads.
A cabin frame 20xe2x80x2 is formed in front of the load-carrying platform 30xe2x80x2 so as to surround the driver""s seat 4. The cabin frame 20xe2x80x2 has front and rear portions 21xe2x80x2, 22xe2x80x2 including vertical members and horizontal members which are extended between the vertical members. The front, rear, right and left sides of the driver""s seat 4 is surrounded by the cabin frame 20xe2x80x2. The cabin frame 20xe2x80x2 is formed by assembling steel pipes or the like so as to protect the driver. A roof or a hood, not shown, can be attached to the cabin frame 20xe2x80x2 to screen the driver""s seat 4 from rain and sunshine, and lighting devices 7 can be attached to the cabin frame 20xe2x80x2 for illumination to facilitate work at night.
As shown in FIG. 6B, lower end portions of the front portion 21xe2x80x2 of the cabin frame 20xe2x80x2 are held on a front part of the body frame 10 by joints 23xe2x80x2 fastened to the body frame 10 with bolts. Lower end portions of the rear portion 22xe2x80x2 of the cabin frame 20xe2x80x2 are held on an upper part of the load-carrying platform 30xe2x80x2 by joints 26xe2x80x2 fastened to the load-carrying platform 30xe2x80x2 with bolts.
The above-mentioned four-wheeled utility vehicle has the following problems.
a) The joints 26xe2x80x2 holding the lower end portions of the rear portion 22xe2x80x2 are fastened to the upper part of the load-carrying platform 30xe2x80x2. Therefore, it is difficult to lift or tilt the load-carrying platform 30xe2x80x2 or to remove the load-carrying platform 30xe2x80x2 from the body frame 10. Work for unloading the load-carrying platform 30xe2x80x2 and work for the maintenance of mechanical devices including the engine provided under the load-carrying platform are facilitated if the load-carrying platform 30xe2x80x2 can be tilted by lifting the front part thereof or can be removed easily from the body frame 10. However, when those components of the cabin frame 20xe2x80x2 are held by the joints 26xe2x80x2 fastened to load-carrying platform 30xe2x80x2, the cabin frame 20xe2x80x2 must be separated from the joints 26xe2x80x2 before lifting or removing the load-carrying platform 30xe2x80x2, which takes considerable time and labor.
b) On the other hand, if the lower end portions of the rear portion 22xe2x80x2 of the cabin frame 20xe2x80x2 are joined to the body frame 10 which is underlying the load-carrying platform 30xe2x80x2, the load-carrying platform 30xe2x80x2 can be relatively easily lifted or removed. However, the length of the rear portion 22xe2x80x2 must be increased to join the lower end portions of the rear portion 22xe2x80x2 to the body frame 10. As a result, the rear portion 22xe2x80x2 should be formed by bigger pipes or pipes having bigger wall thickness to ensure a sufficient rigidity to the rear portion 22xe2x80x2. Therefore, the weight of the cabin frame 20xe2x80x2 will considerably increase. To enable the cabin frame 20xe2x80x2 to withstand an external back-and-forth force acting on the upper end of the cabin frame 20xe2x80x2, most part of the moment must be born by the joints joining the lower end portions of the rear portion 22xe2x80x2 and the body frame 10. Therefore, the joints must be built very strong, and the rear portion 22xe2x80x2 of the cabin frame 20xe2x80x2 must be formed from thick, strong pipes or the like. As a result, the cabin frame will become considerably heavy. The rigidity of the cabin frame 20xe2x80x2 can be enhanced by extending guardrails 4a from the rear portion 22xe2x80x2 as shown in FIG. 6B and joining the guardrails 4a to the body frame 10. However, the weight of the cabin frame 20xe2x80x2 will increase. Moreover, the guardrails 4a obstruct the driver""s getting on and off the utility vehicle.
The present invention has been made to solve such problems and it is therefore an object of the present invention to provide a four-wheeled utility vehicle provided with a rigid, lightweight cabin frame capable of facilitating tilting a load-carrying platform of the four-wheeled utility vehicle.
According to the present invention, a four-wheeled utility vehicle has: a body frame; a driver""s seat disposed on the body frame; a load-carrying platform having a front end portion and a rear end portion, the load-carrying platform being disposed behind the driver""s seat; a cabin frame having a rear portion and surrounding the driver""s seat, the cabin frame being disposed in front of the load-carrying platform, the rear portion of the cabin frame including a lower end which is positioned on a level below the load-carrying platform and a middle portion which is located on a middle level in a vertical direction within the rear portion, the lower end of the rear portion being joined to the body frame, and the middle portion of the rear portion being bound by the front end portion of the load-carrying platform in an easily separable manner.
Unless otherwise specified, the words xe2x80x9cfrontxe2x80x9d, xe2x80x9crearxe2x80x9d, xe2x80x9crightxe2x80x9d, xe2x80x9cleftxe2x80x9d are used herein to signify position or direction with respect to the direction of forward travel of the four-wheeled utility vehicle, and the words xe2x80x9clateralxe2x80x9d, xe2x80x9cback-and-forthxe2x80x9d, xe2x80x9cverticalxe2x80x9d and xe2x80x9chorizontalxe2x80x9d are not used in strict sense and is used to signify substantially lateral, substantially back-and-forth, substantially vertical and substantially horizontal. The phrase xe2x80x9c(be bound) in an easily separable mannerxe2x80x9d signifies that the cabin frame is bound by the load-carrying platform such that the cabin frame can be easily disconnected from the load-carrying platform without practically impairing the tilting ability of the load-carrying platform.
Since the lower end portions of the rear portion of the cabin frame are not fastened to the load-carrying platform, the load-carrying platform of the four-wheeled utility vehicle can be turned upward and downward (tilted). The load-carrying platform can be easily and quickly turned upward and downward by hand or a mechanical device only if the middle portion of the rear portion of the cabin frame is released from the load-carrying platform without requiring work for unfastening a joint and removing the cabin frame. The tiltable load-carrying platform facilitates work for unloading the load-carrying platform or work for the maintenance of mechanical devices underlying the load-carrying platform.
Since the lower end of the rear portion of the cabin frame is joined to the body frame and the middle portion of the same is bound by the load-carrying platforms, the cabin frame is rigid and is able to withstand load exerted thereon. A large moment exerted on the rear portion by the load is counterbalanced by reaction forces produced in the middle portion bound by the load-carrying platform and the lower end joined to the body frame. Since the middle portion and the lower end of the rear portion can be spaced a sufficiently great distance apart, reaction forces at the middle portion and the lower end of the rear portion are not excessively high. Therefore, stresses are induced in the rear portion of the cabin frame in a mode quite different from that in which stresses are induced in the rear portion of the cabin frame of the known four-wheeled utility vehicle that bears the moment only by the lower end of the rear portion. Although the forces exerted on the cabin frame are transmitted to the load-carrying platform, any problem does not arise because the load-carrying platform is firmly supported on the body frame. For example, the load-carrying platform is supported by support means including pivotal member on which the load-carrying platform is turned for tilting.
The rigidity of the cabin frame is enhanced since the middle portion of the rear portion is bound by the load-carrying platform. Therefore, an increase in the weight of the cabin frame can be limited to the least necessary extent. The middle portion of the rear portion of the cabin frame can be bound by the load-carrying platform with only an additional small part because the rear portion of the cabin frame is very close to the load-carrying platform. The joint of the lower end of the rear portion and the body frame do not need to be very strong. The rear portion does not need to be formed from very strong materials, such as thick pipes. Consequently, the cabin frame can be formed in a lightweight structure. An increase in weight of the cabin frame due to the binding of the middle portion of the rear portion thereof by the load-carrying platform is smaller than that due to the connection of the rear portion to the body frame by guardrails or the like. The cabin frame does not obstruct driver""s getting on and off the utility vehicle.
Preferably, the rear portion of the cabin frame has a plurality of vertical members and a horizontal crossbar by which the vertical members are connected. The load-carrying platform can be turned such that the front end portion of the load-carrying platform is raised relative to the rear end portion of the load-carrying platform. The load-carrying platform is provided with a hooking member at the front end portion of the load-carrying platform, the hooking member having an eye opening which is opened downward. The rear portion of the cabin frame is restrained from free movement by the hooking member which is hooked over the crossbar when the front end portion of the load-carrying platform is placed at its normal position.
The load-carrying platform of the four-wheeled utility vehicle can be tilted by lifting up the front end portion thereof. Therefore, the load-carrying platform can he easily unloaded. Work for the maintenance of the mechanical devices underlying the load-carrying platform is facilitated.
The rear portion of the cabin frame can be bound by the load-carrying platform by bringing the hooking member from above into engagement with the crossbar. Therefore, the hooking member can be disengaged from the crossbar simply by raising the front end portion of the load-carrying platform and be brought into engagement with the crossbar simply by lowering the front end portion of the load-carrying platform. Any special operation is not necessary at all for disengaging the hooking member from and engaging the same with the crossbar. Once the hooking member is engaged with the crossbar, the crossbar is surely restrained by the hooking member from free movement in all directions excluding movements in a downward and a lateral directions.
The crossbar can be effectively used when the same is attached to the vertical members of the rear portion of the cabin frame and the hooking members attached to the front end of the load-carrying platform are brought into engagement with the crossbar. The load-carrying platform is a rigid structure formed by attaching side walls and end walls to a deck, the cabin frame is formed by assembling rods or pipes, such as steel pipes, so as to surround the driver""s seat. The rigidity of the cabin frame can be effectively enhanced by the crossbar. Since the conventional cabin frame is provided with a crossbar on its rear members, any special crossbar does not need to be attached to the conventional cabin frame when incorporating the present invention into the conventional cabin frame.
Preferably, the load-carrying platform having a pair of the hooking members which are attached to right and left end portions of the front end portion of the load-carrying platform, respectively.
The hooking members attached to the right and the left end portion of the front end of the load-carrying platform are able to exercise a function of binding the crossbar by the load-carrying platform more effectively. The load-carrying platform has the side walls placed on the right and the left side of the deck, and the front and the rear end of the deck, respectively, to define a space for containing cargo. The opposite ends of the front end wall is joined to the front ends of the right and the left side wall. Therefore, the front right and the front left end portion of the load-carrying platform is more rigid than a middle portion of the front end of the load-carrying platform. Generally, the vertical members of the rear portion are disposed at the right and the left end of the rear portion of the cabin frame and hence the crossbar is joined to the vertical members at positions near the right and the left side of the body frame. Therefore, opposite end portions of the crossbar are rigid and are more difficult to deform than a middle portion of the same. Thus, the hooking members attached to the front right and the front left end portion of the load-carrying platform are able to bind the cross bar securely to prevent the deformation of the cabin frame effectively.
Preferably, a small clearance is formed between an outer surface of the crossbar and a periphery of the eye opening when the front end portion of the load-carrying platform is placed at the normal position.
Since the clearance is formed between the crossbar and the hooking member when the front end of the load-carrying platform is placed at the normal position, the load-carrying platform can be smoothly lifted up and lowered. It is possible that the crossbar and the hooking member touch each other and noise is generated because the cabin frame and the load-carrying platform vibrate while the four-wheeled utility vehicle is traveling. Noise generation can be prevented by increasing the size of the clearance to an extent that the crossbar and the hooking member do not touch each other due to vibration of the crossbar and the hooking member.
The clearance between the cross bar and the hooking member is small enough to make the hooking member attached to the load-carrying platform to exercise effectively their function to bind the crossbar attached to the cabin frame when the cabin frame is loaded. In other words, when the cabin frame is deformed elastically, the crossbar touches the hooking member and is restrained from further movement relative to the hooking member. Therefore, plastic deformation of the cabin frame can be prevented.
Preferably, a cushioning member is interposed between the crossbar and the hooking member. The generation of noise can be prevented by the cushioning member.
Preferably, the load-carrying platform is provided with a horizontal bar at the front end portion of the load-carrying platform. The load-carrying platform can be turned such that the front end portion of the load-carrying platform is raised relative to the rear end portion of the load-carrying platform. The cabin frame is provided with a hooking member at the rear portion of the cabin frame, the hooking member having an eye opening which is opened upward. The rear portion of the cabin frame is restrained from free movement by the horizontal bar with which the hooking member is engaged when the front end portion of the load-carrying platform is placed at its normal position.